The disclosure of Japanese Patent Application No.2001-085525 filed on Mar. 23, 2001, including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of Invention
The invention relates to a vehicle performance evaluation test method and apparatus, and more particularly to a vehicle performance evaluation test method and apparatus for evaluating a vehicle performance using a pressing device (an actuator) that automatically applies a depressing force to a control member to be operated by a vehicle operator.
2. Description of Related Art
In order to conduct a test for evaluating a braking performance such as a braking distance and deceleration of a vehicle, for example, a motor vehicle, a brake pedal needs to be depressed with a predetermined pressing force or the brake pedal needs to be depressed so as to achieve a predetermined deceleration while keeping the vehicle in a running state. It is, however, difficult for the vehicle operator to accurately operate the brake pedal as described above.
JP-A-11-132914 discloses a vehicle performance evaluation test apparatus that automatically operates the brake pedal for the vehicle operator. The test apparatus is fixedly set under the seat of the vehicle and provided with a control rod which extends in a longitudinal direction of the vehicle and a driving mechanism which drives the control rod forward and backward. The control rod serves to automatically operate the brake pedal with its tip such that the performance evaluation test is conducted with respect to the braking operation of the vehicle.
With the aforementioned test apparatus, the brake pedal can be automatically depressed, and therefore the vehicle operator is able to conduct the evaluation test for the braking operation of the vehicle while driving the vehicle without operating the brake pedal. Furthermore, since a main portion of the test apparatus is fixedly set under the seat, the possibility of interfering with the vehicle operator when he/she enters or exits the vehicle or to perform smooth driving is reduced.
However, before conducting the evaluation test, the aforementioned test apparatus has to be installed in the vehicle by temporarily detaching the seat. After the test apparatus is installed in the vehicle, the seat is attached again such that the test can be started. Meanwhile, after the test is finished, the test apparatus is removed from the vehicle by temporarily detaching the seat. After the test apparatus is removed from the vehicle, the seat is attached again. Conducting the performance test, thus, requires much time and labor as aforementioned, preventing efficient and smooth testing.
The test apparatus is fixedly set under the seat, by which the direction for depressing the brake pedal by the control rod is defined. Accordingly, the direction for depressing the brake pedal cannot be adjusted. An axial tension of the control rod is detected by a load sensor attached to the control rod as a depressing load applied to the brake pedal. In the aforementioned test apparatus, the depressing load applied by the tip of the control rod to the brake pedal cannot be detected accurately, requiring further improvement in the accuracy of the evaluation test.
It is one object of the invention to provide a performance evaluation test method for automatically applying pressure to a control member using the seat efficiently without requiring detaching/attaching the seat.
According to one aspect of the invention, there is provided a method for conducting a vehicle performance evaluation test by automatically depressing a control member of the vehicle to be depressed by a vehicle operator using an actuator of a vehicle performance evaluation test apparatus. The method includes the steps of providing the actuator having a first end and a second end for pressing the control member, fixing the first end of the actuator to a seat of the vehicle, engaging the second end of the actuator with the control member of the vehicle, and causing the actuator to exert a depressing force to depress the control member relative to the seat so as to automatically depress the control member. Another aspect of the invention relates to a vehicle performance evaluation test apparatus which includes an actuator that is provided with a first end fixed to a seat of the vehicle and a second end engaging with the control member. The actuator automatically presses a control member of the vehicle to be depressed by an operator of the vehicle, and is operable to generate a force to depress the control member relative to the seat of the vehicle. The actuator further includes a rod member movable in a longitudinal direction of the vehicle so as to depress the control member.
One end of the actuator is fixed to the seat and the other end is engaged with the control member. The actuator generates the force for relatively pressing the control member with respect to the seat to automatically press the control member. As a result, the evaluation test for the vehicle performance can be performed requiring no need for removing or installing the seat.
According to one aspect of the invention, a direction of depressing a force receiving surface of the control member is adjusted to a predetermined direction by the actuator prior to automatic operation of the control member by the actuator. The actuator is adjusted such that the pressing direction with respect to a force receiving surface of the control member is aligned with a predetermined direction prior to automatic application of the depressing force to the control member by the actuator. Therefore, the evaluation test for the vehicle performance can be started in the state where the pressing direction with respect to the force receiving surface of the control member is accurately aligned with the predetermined direction.
According to one aspect of the invention, a depressing load applied to the force receiving surface of the control member by the second end of the actuator is detected, and the depressing operation is controlled on the basis of the detected depressing load. The depressing load applied to the force receiving surface of the control member from the end of the actuator is detected, and the pressing by the actuator is controlled based on the detected depressing load. Therefore the evaluation test for the vehicle performance can be properly performed by accurately controlling the depressing force applied to the control member from the end of the actuator.
According to one aspect of the invention, the depressing force applied to the control member is reduced by generating a force for driving the second end of the actuator in a direction reverse to the direction of the depressing force. The actuator is capable of generating a force for driving the end thereof in the pressing direction and in the reverse direction. The actuator generates the force to drive the end thereof in the direction reverse to the pressing direction such that the depressing force applied to the control member is reduced. This makes it possible to increase or decrease the depressing force applied to the control member with high response, thus reducing overshoot upon increase in the depressing force of the actuator to a target value or fluctuation caused by maintaining the depressing force at the target value compared with the conventional test method or apparatus that allows the depressing force to be increased or decreased only in the pressing direction. Accordingly the depressing force applied to the control member can be reduced or eliminated efficiently upon completion of the test.
According to one aspect of the invention, a state in which the first end of the actuator is fixed to the seat is adjusted by the vehicle operator who is seated on the seat prior to automatic depression of the control member. The fixed condition of the end of the actuator with respect to the seat can be adjusted by the vehicle operator already seated on the seat before automatically pressing the control member by the actuator. Therefore, even if the fixed condition of the end of the actuator with respect to the seat is affected when the vehicle operator is seated on the seat, the fixed condition of the end of the actuator can be adjusted such that it is surely fixed in accordance with the predetermined fixed condition with respect to the seat, and thereby the evaluation test for the vehicle performance can be conducted with the one end of the actuator surely fixed in accordance with the predetermined fixed condition.
According to one aspect of the invention, the actuator is able to adjust a direction of depressing a force receiving surface of the control member to be pressed prior to automatic operation of the control member by the actuator. The actuator is allowed to adjust the pressing direction with respect to the force receiving surface of the control member. Therefore, the actuator is adjusted to align the direction of the depressing force applied to the force receiving surface of the control member with the predetermined direction. This makes it possible to start the test in the state where the pressing direction to the force receiving surface of the control member is aligned with the predetermined direction.
According to one aspect of the invention, there is provided a load detector disposed at the second end of the actuator and operable to detect a depressing load applied to the force receiving surface of the control member by the second end of the actuator. The actuator is provided with the load detector at its end so as to detect the depressing load applied to the force receiving surface of the control member from the end of the actuator. Therefore, the evaluation test for the vehicle performance can be properly performed by accurately controlling the depressing force to be applied to the control member from the end of the actuator.
According to one aspect of the invention, the actuator is capable of generating a force to drive the second end in a direction in which the control member is depressed and in a direction reverse thereto. The actuator is capable of generating a force for driving its end in the pressing direction and in the reverse direction. The actuator generates the force to drive the end thereof in the direction reverse to the pressing direction such that depressing force applied to the control member is reduced. This makes it possible to increase or decrease the depressing force applied to the control member with good response. Unlike the conventional test method or apparatus that allows the depressing force of the actuator to be increased or decreased only in the pressing direction, overshoot upon increase in the depressing force of the actuator to a target value or fluctuation caused by maintaining the depressing force at the target value may be reduced. Accordingly the depressing force applied to the control member can be reduced or eliminated efficiently upon completion of the test.
According to one aspect of the invention, there is provided an adjustment that adjusts a state in which the first end of the actuator is fixed to the seat and is operable by the vehicle operator who is seated on the seat. There is provided the adjustment for adjusting the fixed condition of one end of the actuator with respect to the seat, which can be operated by the operator seated on the seat. Therefore, even if the fixed condition of the end of the actuator with respect to the seat is affected when the vehicle operator is seated on the seat, the fixed condition of the end of the actuator can be adjusted such that it is surely fixed in accordance with the predetermined fixed condition with respect to the seat, and thereby the evaluation test for the vehicle performance can be performed with the one end of the actuator surely fixed in accordance with the predetermined fixed condition.
According to one aspect of the invention, there is provided an attachment mounted on the second end of the actuator to be fixed to the control member. The attachment is operable to disconnect the second end of the actuator from the control member when a force equal to or greater than a predetermined value is exerted between the control member and the second end of the actuator in a direction such that the control member moves apart from the second end of the actuator.
The actuator is provided with the attachment at its end. When the force equal to or greater than a predetermined value is exerted between the control member and the actuator in the direction moving apart from each other, the end of the actuator is disengaged from the control member. Therefore, the vehicle operator is allowed to operate the control member by applying a strong force to the control member so as to be disconnected from the actuator when the vehicle operator finds it necessary to pressurize the control member even in the middle of the evaluation test.
According to one aspect of the invention, there is provided a releasable coupling that disconnects the first end of the actuator from the seat and disengages the second end of the actuator from the control member. The releasable coupling is operable by the vehicle operator who is seated on the seat. The releasable coupling serves to disconnect the end of the actuator from the seat, and to disengage the other end of the actuator from the control member. The vehicle operator is allowed to operate the releasable coupling while being seated on the seat. Therefore the possibility for the actuator to hinder the vehicle operator from smoothly getting off the vehicle can be decreased. The actuator, thus, can be easily removed upon completion of the evaluation test.
According to one aspect of the invention, the control member takes a form of a braking control member. Therefore, the evaluation test can be automatically conducted by automatically depressing the braking control member using the actuator.
Preferably, a length of the actuator is adjustable when in a non-operational state, and the actuator is adjusted to align a direction of depressing the force receiving surface of the control member with a predetermined direction of a position of the seat as viewed in a longitudinal direction of the vehicle.
Preferably, a depressing operation of the actuator is controlled on the basis of a deviation between a target depressing load and the detected depressing load.
Preferably, deceleration of the vehicle is detected, and a depressing operation of the actuator is controlled on the basis of a deviation between a target deceleration and the detected deceleration.
Preferably, the actuator takes the form of a depressing force generator having a first end and a second end, a seat-side attachment that fixes the first end of the depressing force generator to the seat of the vehicle, and a control-member-side attachment that fixes the second end of the depressing force generator to the control member.
The actuator may be provided with a coupling that detachably couples the depressing force generator with the seat-side attachment.
Preferably, the depressing force generator takes the form of a cylinder having a piston, a first chamber and a second chamber defined by the piston, and a pressure within at least one of the first and the second chambers is controlled. A pressure within the other chamber of the cylinder may be controlled to a constant pressure that is higher than an atmospheric pressure.
The cylinder may take the form of a pneumatic cylinder.
The first chamber and the second chamber of the cylinder may be allowed to be open to an ambient air when the vehicle performance evaluation test apparatus is in a non-operational state.
The seat-side attachment may include a seat engaging member having a horizontal portion that is placed on a seat body of the seat and a vertical portion that abuts on a front end of the seat body.
The seat side attachment may include a lower engaging member that engages with a lower surface of the seat body of the seat so that one end of the depressing force generator is fixed to the seat by holding the seat body between the horizontal portion of the seat engaging member and the lower engaging member while the vertical portion of the seat engaging member abuts on the front end of the seat body.
The seat-side attachment may further include a clamp load adjustment that adjusts a clamp load applied to the seat body. The seat-side attachment is operable by the vehicle operator who is seated on the seat.
The depressing force generator may have a spherical portion formed on the second end to be connected to the control member. The control-member-side attachment may include a socket that receives the spherical portion, and a mounting member that mounts the socket to the control member so that the depressing force is transmitted from the socket to the control member.
The mounting member may include an abutting member that abuts on a force receiving surface of the control member to be pressed such that a load detector is compressed between the abutting member and the socket member.
The control-member-side attachment may include a base member that supports the socket such that the depressing force is allowed to be transmitted from the socket to the control member, and a holding plate that is fixed to the base member and prevents the spherical portion from coming off the socket.
The holding plate may deform when a force equal to or greater than a predetermined value is exerted in a direction in which the spherical portion comes off the socket so as to allow the spherical portion to come off the socket.